I have headphones and 2.0 speakers so the only options I ever use under Analog Out are: Headphone and 2 Speakers.
For competitive gaming in BF3 using headphones:
For immersive listening to music on headphones or 2.0 speakers:
Dolby Headphone sounds great for movies and in those cases it looks like this:
Now depending on the source engine, you might need to mix and match some options like:
Audio Channel-----------Analog Out
8--------------------------headphones or 2 speakers
6--------------------------headphones or 2 speakers
4--------------------------headphones or 2 speakers
You could even play with Dolby Headphone and see how that sounds to your ear. I like to toss a grenade out in front of me and turn my character so the nade goes off by my right ear, then my left, then tossing another and running and jumping through it (can you jump in source?) Just fight w/ the explosions and see if you can have a friend come from behind left shooting towards you, just mix it up. Have fun with it! All this assumes those are 2 channel headphones. I spent about a minute or two trying to understand the Siberia, but I'm not really sure of it's pros/cons/etc.
Edit: found them:
Pros
-Extremely Comfortable (Beyer velour ear muffs as large as AKG Q701)
-Retractable microphone (would be SO much better than the Zalman ZM1-mic clip on that picks up all sounds known to man)
-Good passive noise reduction (Not sure who isolates the best, but it would be nice to have open for larger soundstage w/ more accurate cues and closed for LAN parties)
-Price (is not going to matter if even 3 or 4 of these things get melded together perfectly.)
-Comes in a wide variety of colors (I like this, I really do. Black band, Yellow muff to match my home speakers. :D)
Cons will become Pros if Steelseries could work together w/ Sennsheiser/AKG/Beyer/Audio Technnica/Denon
-Slightly muddy bass---Beyer 880, Denon D2000, Sennheiser HD600, AKG Q701
-Leather ear pads can make you sweat--Beyer Velour, Sennheiser Velour, AKG Velour get together in the room and bake the best velour!
-Small ear cups so not really “full sized”--Death of supra aural, all phones need to be fitting like a great pair of Asics or Brooks running shoes.
-Smaller sound stage than what we would like to hear--Sennheiser HD800, AKG Q701